This invention relates to nonwoven absorbent wiping products. The invention particularly relates to dispensable oil indicating absorbent cosmetic wiping products.
Nonwoven webs of the thermoplastic fibers have been used extensively in the past for their known ability to absorb oil or grease such as described in U.S. Pat. No. 4,307,143 (Meitner); U.S. Pat. No. 4,328,279 (Meitner et al.) and U.S. Pat. No. 4,426,417 (Meitner et al.), which patents relate to industrial oil absorbency materials. U.S. Pat. No. 4,587,154 to Hotchkiss et al. also employs a nonwoven web, made of meltblown thermoplastic fibers, for use in industrial applications. The Hotchkiss et al. patent describes point bonding the formed web to give the material integrity. The web is then sprayed with, e.g., carboxy methyl cellulose, to permit the grease or oil to be released and the web reused.
Oil absorbing nonwoven wipes for removing facial oil have also been described in the art. These wipes must be thin, conformable and non-abrasive, considerations not relevant to industrial oil absorbent materials. A significant amount of oil continuously oozes out of the face, particularly the nose, cheek, forehead and middle forehead. To maintain cleanliness and to improve the spreadability of cosmetics it is important to remove any excess oil or sebum. Soap and water work to some extent but there are always times when one is not able to wash. Dry methods of removing these facial oils include the use of thin oil absorbent wipe materials.
Conventional paper type wipes have been used to remove facial oil. For example, natural or synthetic papers using vegetable fibers, synthetic pulp or kenaf have been used. These oil absorbent papers however are generally irritating to the skin due to the hard and stiff nature of the fibers. To improve smoothness, these papers have been calendered and/or coated with powders such as calcium carbonate and sizing agents. Calendering however is not necessarily permanent and surface fibers can reform into a rough surface unless substantial amounts of binder or sizing agents are used, which decrease oil absorption. Paper wipes are also poor indicators as to their effectiveness as papers generally do not significantly change appearance when they have absorbed oil or sebum.
Improvements to oil absorbing papers are described in Japanese Kokai No. 4-45591 which teaches adhering porous spherical beads onto the surface of an oil absorbing paper so as to solve the problems caused by calendering or coating of paper, with powders such as calcium carbonate powders, and to increase the capacity of these paper to absorb sebum. Japanese Unexamined Patent Publication (Kokai) No. 6-319664 discloses a high-density oil absorbing paper produced by mixing (a) a pulp material containing vegetable fibers, as the main component with (b) an inorganic filler, followed by paper-making to form a paper with a basis weight of 0.7 (g/cm2) or more. However, the oil absorbing papers disclosed in these patent publications still have a limited capacity to absorb oil or sebum and little indicating function as there is little change in opacity or color in the paper when oil is absorbed. Difficulty in confirming oil means that users of the oil clearing paper can not evaluate if or how much sebum was removed from the users"" face using the oil absorbing paper such that makeup can be applied with confidence.
An oil absorbing paper for sebum is also disclosed in Japanese Examined Patent Publication (Kokoku) No. 56-8606, or U.S. Pat. No. 4,643,939, which describes a cosmetic oil absorbing paper produced by mixing hemp fibers with 10 to 70% by weight of polyolefin resin fibers and making a paper with a basis weight of from 12 to 50 (g/cm2). This paper will allegedly clear upon absorption of oil but still requires conventional papermaking techniques and would be rough to the touch. Japanese Unexamined Utility Model Publication (Kokai) No. 5-18392, discloses an oil absorbing synthetic paper comprising an oil absorbing paper with a smooth surface coating of inorganic or organic powder material such as clay particles, silica fine-particles, and powdered fibers. These oil absorbing papers allegedly have some oil indicating effect by clarifying the paper upon oil absorption thus confirming oil absorption. However, the oil absorption capacity for these papers is lowered by the powder coating and it is still difficult to attain a clear change in the appearance of this type of oil clearing paper after oil absorption.
As described above, oil absorbing webs produced by using plastic fibrous material in place of cellulosic fibrous papers is known. Also, Japanese Unexamined Patent Publication (Kokai) No. 9-335451 (WO99/29220) discloses an oil sheet made of a porous plastic film. This oil absorbing sheet has absorbing higher absorption capacity than the oil absorbing papers and is also is superior in confirming removal of oil following wiping than oil absorbing papers. It is believed that the reason is that these porous plastic films exhibit low transmittance before oil absorption because of irregular reflection of light, but the transmittance increases substantially after the micro-pores of the film are filled with oils producing a large change in the film""s opacity, and therefore appearance. This change in opacity clearly confirms to the user the removal of oil or sebum from his or her skin. U.S. Pat. No. 4,532,937 to Miller describes analytical film for collecting sebum as it is secreted from the sebaceous glands of a subject comprising an open-celled, micro-porous and hydrophobic polymeric film, a fibrous material having coated on one major surface a layer of synthetic, pressure-sensitive adhesive consisting essentially of high molecular weight components. The Miller patent describes its material as having pores of such a size and distribution that the film is opaque or opalescent when the pores are empty or filed with air but can become translucent or transparent upon absorption of a liquid such as sebum. However, the very small pores described for this film or material (less than 0.1 microns) do not provide a material suitable for use in cosmetic applications due to the slow oil absorption rates.
It is an object of the invention to form an oil absorbing sheet having a clear oil indicating function, such as described in WO99/29220, however in a fibrous product that is non-irritating to the skin, is easy to directly manufacture and requires no post-formation coatings or the like and can absorb oil rapidly.
The invention further relates to a method of providing an oil absorbing sheet in a dispensable form.
The present invention is directed to an oil-absorbing wipe product, which is directly formed by a melt-blown fiber forming process. The melt-blown fibrous wipe product indicates oil absorption visually to the user rapidly upon the absorption of oil by a rapid change in opacity. This synthetic fiber wipe is also non-irritating to the skin. The microfine fibers are directly formed by extruding streams of thermoplastic polymer into a hot, high-velocity attenuating airstream. The microfine fibers are then collected at a relatively low basis weight on a collecting surface as a web. This web is then subjected to a controlled calendering and converted into an oil absorbing wipe having an oil indicating function. The resulting oil absorbing wipe web generally is characterized by a basis weight of less than 40 g/M2, a void volume of from about 40 to 80%, an oil absorption capacity of from 0.9 to 6 mg/cm2 and a mean pore size of from 3 to 15 microns. The web is then cut or formed into discrete wipes and these wipes are suitably packaged into a dispensable package of a plurality of wipes. The wipe material has the capability to have a change in transparency after oil absorption of at least 30 (as defined herein). The wipe material is also soft, easy to handle and readily conforms to the user""s face, with a Hand of less than 8 grams, but can be packaged and dispensed as would be a conventional paper tissue or wipe type product.